Liposome Preparation System Case Study - Active Drug-loaded Method

2017-07-16 22:21

In the last issue, we introduced the cases of passive drug-loaded method. Here, We will introduce the active drug-loaded method. Liposome active drug-loaded method mainly includes pH gradient method and ammonium sulfate gradient method, the production process steps include the preparation of phospholipid bilayer, the preparation of buffer, the preparation of ultrafiltration, high pressure homogenization or extrusion, ultrafiltration concentration, Blank liposomal solution preparation, drug coating, filtration and filling. In contrast, the active drug-loaded process is more difficult than passive drug-loaded method, embodied in the encapsulation rate and the amount of drug loading, particle size and its distribution, leakage rate, in vitro release and in vivo tests of drugs, etc.

The typical process of active drug loading is as follows:

The blank liposomes were prepared by cationic gradient method, then the organic phase was removed by ultrafiltration system. The API solution was slowly added to the blank liposomes for drug coating, after tested and filtration, the drugs were finally sent to machine filling.

1. Preparation of organic phase

Adding phospholipids and cholesterol into the tank, and then adding organic solvent In a confined environment, then stirring to make sure raw material was dissolved.

2. Water phase preparation

The amount of feeding water should be accurate controlled by weighing module, after feeding water, adding ammonium sulfate raw materials, stirring to make sure raw material was dissolved, then removing the heat source by a suitable method, at last, saving the compound at a certain temperature (ultrafiltration system or activated carbon adsorption).

3. Preparation of blank liposomes crude

The prepared aqueous phase and the organic phase are added to the mixing tank, and the mixture is stirred for a certain time in the case of the tank temperature control to obtain the crude product of the liposome. The crude product was homogenized by high pressure homogenizer + high pressure extrusion repeatedly, and the average particle size and average particle size were obtained by sampling.

4. Buffer preparation

The buffer material is accurately weighed and added to the water for injection, stirred and dissolved. After the heat source is removed by a suitable method, it is stored at a certain temperature (ultrafiltration system or activated carbon adsorption), and the pH is about 6.2 to 6.8.

5. tangential flow analysis

A large area of ultrafiltration system should be equipped after the blank liposomes crude tank, to adjust the ultrafiltration system membrane package (ultrafiltration column) dialysis parameters, then blank liposomes could be gained after the buffer replaces the aqueous phase (the process can choose batch or continuous) , According to the process design of a certain concentration ratio.

6. Liposomes drug-loaded

Added the accurately weighed prescription amount of the main drug ingredients into the water for injection to get a certain concentration of the solution (buffer solution is also available), then adding the solution to the blank liposomes for drug-loaded after sterilizing, control a certain temperature and open the mixer with low-speed, After mixing, buffer solution can be added to the liposomes optional to improve the encapsulation rate of the products.

7. Machine filling after filtration

Liposome is transferred to buffer tank through a 0.45um and a 0.22um filters After preparation, during this process, samplings should be taken to ensure liposome is aseptic, then after qualified, product is transferred to machine filling by nitrogen, , to ensure that the filling and transportation is automatic and stable.

The above picture shows a production line of automatic liposome preparation system for a well-known pharmaceutical company(made by Tofflon), which includes buffer salt preparation module, organic phase removal module, ultrafiltration system module, high pressure homogenizer / high pressure extrusion module, ultrafiltration concentration module, sterilization filter module, and this project is in the production stage now.

The features of Tofflon’s solution preparation system in this project:

Modular
design, factory production, process display, visualization of the show

Tofflon’s liposome preparation system can
fix the shortcomings of small variety and pilot test, and put forward optimization
process conditions for commercial large-scale solution preparation system, but
according to the different process and other factors, the overall system will
be different, if you need to communicate in detail, please contact with Tofflon
for further discussion.